Conventional communication networks, especially satellite-base communication networks, suffer from an inefficient use of system resources. Inefficiencies may result from the establishment and maintenance of a communication link between subscriber units utilizing differing communication protocols, the assignment of protocol priorities when multiple protocols are possible over a communication link between a given pair of subscriber units, and the utilization of system resources not specifically required by a given communication link between subscriber units.
The establishment and maintenance of a communication link between subscriber units utilizing differing communication protocols are typically possible only in limited cases, such as between a hand-held subscriber unit, e.g., a cellular phone, and a common PSTN (public switched telephone network) unit (e.g., a standard telephone in a local land-based telephone network). However, two dissimilar subscriber units, each capable of communicating with a PSTN telephone via the communication network, may be unable to communicate with each other should their protocols differ. Any attempt to complete such a connection would result in the call being dropped. Dropping the call often results in poor customer satisfaction and a loss of revenue.
Should multiple communication protocols be possible over a communication link between a given pair of subscriber units (i.e., each subscriber unit and the network itself may communicate via any one of a multiplicity of common communication protocols), then a method of prioritizing those protocols is desirable. A problem arises as to how and where in the system protocol prioritization is to be performed. The priorities of the provider and the priorities of the subscriber often conflict. For example, the ideal protocol for the provider may be one that optimizes the use of system resources, (e.g., places the least burden upon the network and/or incurs the lowest system overhead cost). For the subscriber, on the other hand, the ideal protocol may be one that minimizes subscriber costs (not the same as minimizing provider costs), or maximizes quality. Under such conditions, a problem arises in determining the appropriate protocol to be used.
Related to the problem of protocol prioritization discussed above is the problem of changing that prioritization in accordance with the requirements of the subscriber. For example, in a first call, a subscriber may simply be interested in a routine voice transmission and opt for the least-expensive voice protocol available for the call. Conversely, in a second call, the same subscriber may desire a highest-quality voice protocol, even though such a protocol may be associated with higher cost. The least-expensive and the highest-quality protocols are not likely to be the same protocol. Therefore, provisions need be made to alter the protocol priority according to the requirements of the subscriber. This is not feasible with conventional communication networks.
Also, in the majority of conventional communication networks, once resources have been allocated to a given communication link between two subscriber units, those resources remain allocated until the call is complete and the link is severed. This occurs in spite of the fact that the resources required to initiate the communication link are not necessarily the resources required to maintain the link. In those conventional communication networks that do provide for resource reallocation, no consideration is given to the preservation of those resources allocated to the translation and/or prioritization of protocols. The reallocation of resources using conventional reallocation techniques in a communication network enhanced to provide protocol translation and/or prioritization would therefore result in the dropping of calls.
What is needed, therefore, is an apparatus and methodology with which a communication network may establish and maintain a communication link between two subscriber units having potentially differing communication protocols and translating those protocols as required without dropping any such links.